Unused Engine Oil That is 10 years Old. Would you use it in your engine?

Bronco Bullfrog

Back in 2014 I bought 20 litres of 10w 40 semi synthetic engine oil from Costco in the UK. It's an American brand called Chevron. I had previously bought the same quantity & used all of it as I used to do a fair bit of commuting to work. I changed jobs & did nowhere near as much driving as I used to. As a result I still have a quantity of 10 year old unused oil in my shed. The container shows a fill date of 16/07/2014.

I do my own servicing. I have kept the container in my shed with the cap tightened & used oil from it whenever an oil change was due. My last oil change with it was 2 years ago. My car is due for an oil change so was just wondering what people's opinion would be on using oil that has never been used & kept in it's container for the past decade. Would it still be OK to use, or will the oil have degraded significantly?

I thought I might use this ten year old oil for 3000 or 4000 miles & then change it again with newer oil. I'm currently only doing around 3000 miles per year.

Or how about adding an oil treatment to it like STP or Carlube Oil Treatment to enhance its performance?

Thanks in advance for any advice.

Cheers.

Raichų

no I wouldn’t even dream of using it.

mikeecho

Use it in a lawnmower.

Or bring it to your local Civic Amenity Site.

I wouldn't put it into a car.

junkyarddog

Semi synthetic oils have a shelf life of approx 8 years.

It's probably still ok to use,but if you're unsure best just recycle it and buy some new stuff.

MarkR

I had the same question about a year ago, and contacted Castrol who made it. They didn't recommend using it. Mate is a mechanic and I gave him it to flush engines with.

crybaby

I'd skip the 10-year-old oil. Even sealed, it can degrade. If you use it, mix it with fresh oil, but it’s probably best to invest in a new batch.

selectamatic

I'd use it. Heat cycles and carbon deposits degrade oil.

Sitting on the shelf isn't going to change it massively.

Since it's 10w40 it's surely going into a relatively simple petrol engine? If so I'd have absolutely no reservations about using it.

antodeco

In fairness, the oil is probably 10 million years old already. Just put into a can 10 years ago! 😁

Whocare

I would would use it but instead of my usual 10.000 miles oil changes might drop back to 6000

easygoing39

I'd stick it in for the 3,000 miles and change it then for new oil.It'll be grand for pottering around or cruising on a motorway.However,if your driving a hothatch or like to rev her out to the redline I'd be sticking in brand new in date oil.

o1s1n

https://www.boards.ie/discussion/comment/122674919#Comment_122674919

😁

Not sure the synthetic part of the mix is quite 10 million years old!

mickdw

Id use it if going into something fairly ordinary which looking at the grade, it seems to be.

greasepalm

Interesting question as did not know the answer either , use it for oil can lube jobs and chainsaw hedge trimmer but thats a lot of oil to use up.

BrianD3

If it feels, smells, looks and tastes like new oil, I'd use it. OK maybe I'd skip the taste test.

Raichų

https://www.boards.ie/discussion/comment/122675919#Comment_122675919

I don’t know I think that’s frankly the most important test.

horse7

Could you get a sample tested?

User1998

https://www.boards.ie/discussion/comment/122682596#Comment_122682596

Probably be cheaper to just buy new oil

kindalen

If the container has been opened I wouldn't as many of these oils are hygroscopic and as such will draw water directly from humid air above.

extra-ordinary_

https://www.boards.ie/discussion/comment/122684560#Comment_122684560

That's brake fluid no?

kindalen

https://www.boards.ie/discussion/comment/122684615#Comment_122684615

All the oils from petroleum are hydroscopic

Bronco Bullfrog

https://www.boards.ie/discussion/comment/122674651#Comment_122674651

I was planning on using it in a 2.0 Hdi Diesel engine (the car is a 21 year old Peugeot 406 Hdi). Do you think it'll be Ok in a diesel engine?

Bronco Bullfrog

Yeah that's what I was planning to do with it, I only did about 3000 miles per year. Cheers.

selectamatic

https://www.boards.ie/discussion/comment/122686777#Comment_122686777

I'd put a decent quality 5w30 in that.

They're a great car and getting rare on the roads you're better off treating it right.

Keep the 10w40 for something else that actually takes 10w40 oil or sell it on adverts or something, don't pay to get rid of it anyways.

mickdw

https://www.boards.ie/discussion/comment/122686777#Comment_122686777

They are a pretty modern diesel for 21 years old so need the right old. That was never the right oil for that. Don't use it.

Bronco Bullfrog

https://www.boards.ie/discussion/comment/122692617#Comment_122692617

You say that was never the right oil (10w 40) for a 2.0 litre Hdi Peugeot engine? What makes you say that?

mickdw

We ran a 406 from new when the hHDI engine was introduced and I'm certain it was fully synthetic oil that was required and I'm thinking a 5w30 or 5w40.

Definitely not a semi synthetic 10w40.

Bronco Bullfrog

I have the original Peugeot maintenance booklet for the car which states 10w 40, 5w 30, or 5w 40 (for cars fitted with particle filter) are recommended. There is also six years of service history with the car from two different Peugeot dealers for its first six years and their invoices both state 10w 40 Semi synthetic oil was used when serviced. There is an owners club for the 406 in the UK I checked with them & they said most of their members use 10w 40 for Summer and Winter use. The Haynes manual states ACEA B3 which equates to 10w 40 I guess my question really was referring to the age of the oil I have being ten years old and wether it could be still used in such a diesel engine.

mickdw

Interesting.

I checked there now and I see as you say that 10w 40 is approved. The 5w30 and 5w40 fully synthetic I had in my head are also correct.

I'm surprised by that and certainly was not what we used when we bought it new but everyday is a school day as they say.

I'd use the oil you have so.